Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752553AbaJYTDJ (ORCPT ); Sat, 25 Oct 2014 15:03:09 -0400 Received: from mail-lb0-f177.google.com ([209.85.217.177]:65339 "EHLO mail-lb0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752434AbaJYTDG (ORCPT ); Sat, 25 Oct 2014 15:03:06 -0400 MIME-Version: 1.0 In-Reply-To: <20141025091537.GA11433@gmail.com> References: <20141025091537.GA11433@gmail.com> From: Andy Lutomirski Date: Sat, 25 Oct 2014 09:05:05 -0700 Message-ID: Subject: Re: vmalloced stacks on x86_64? To: Ingo Molnar Cc: Linus Torvalds , "linux-kernel@vger.kernel.org" , "H. Peter Anvin" , X86 ML Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Oct 25, 2014 2:15 AM, "Ingo Molnar" wrote: > > > * Andy Lutomirski wrote: > > > Is there any good reason not to use vmalloc for x86_64 stacks? > > In addition to what hpa mentioned, __pa()/__va() on-kstack DMA > gets tricky, for legacy drivers. (Not sure how many of these are > left though.) Hopefully very few. DMA debugging warns if the driver uses the DMA API, and if the driver doesn't, then IOMMUs will break it. virtio-net is an oddball offender. I have a patch. --Andy > > Thanks, > > Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/